The total cost includes the setup cost + per hour cost.
Let, x represents the time and y represents the total cost.
.... (1)
Let Y represent the cost for B's DJ service.
.... (2)
a. Graphing both the equations give the intersection point (solution) as (4,500)
It means for 4 hours, the total cost of both the DJ's is same at $500.
b. Substitution Method.
Plug y = 125x in equation (1)
Hence, the total cost for 4 hours in both the service is $500.
c. Addition method.
Multiply equation (2) by -1
.... Equation (3).
Add euation (1) and equation (3)
Solution: For x = 4, y = 500 ( same as the previous two methods)
For x = 2, equation (1)
For x = 2, equation (2)
Hence, for 2 hours, DJ B would be a better choice since it would charge $250.
For x = 6 hours, equation (1)
For x= 6, equation (2)
For 6 hours, DJ A would be better option since it charges $650 for 6 hours.
